[libata] SCSI->ATA simulator hacking: INQUIRY command

The SCSI T10 committee is working on a document describing a standard
method for translating ATA<->SCSI, since it being done quite often
these days.  Some of the recommendations are reasonable, and we implement
two here:

* Mirror that ATA 'removeable media' bit into INQUIRY output.
* Change behavior of INQUIRY output field 'product revision' from
  the libata software version number to the first 4 bytes of the
  ATA device's firmware revision number.

Rather than cache the firmware revision in struct ata_device, as was/is
done with two other strings, I took the opportunity to eliminate the
caching of the two other strings, 'vendor' and 'product'.  These strings
are now retrieved as needed from the IDENTIFY [PACKET] DEVICE info page,
since we cache its entire contents.

Retrieving a string from the identify-device page is done via the
helper function ata_dev_id_string(), which is now exported.

This patch winds up making struct ata_device 40 bytes smaller, and
the libata core gets a bit smaller as well.

drivers/scsi/libata-core.c

@@ -818,7 +818,7 @@ static u8 ata_dev_try_classify(struct ata_port *ap, unsigned int device)
  *	@dev: Device whose IDENTIFY DEVICE results we will examine
  *	@s: string into which data is output
  *	@ofs: offset into identify device page
- *	@len: length of string to return
+ *	@len: length of string to return. must be an even number.
  *
  *	The strings in the IDENTIFY DEVICE page are broken up into
  *	16-bit chunks.  Run through the string, and output each
@@ -847,29 +847,6 @@ void ata_dev_id_string(struct ata_device *dev, unsigned char *s,
 	}
 }
 
-/**
- *	ata_dev_parse_strings - Store useful IDENTIFY DEVICE page strings
- *	@dev: Device whose IDENTIFY DEVICE page info we use
- *
- *	We store 'vendor' and 'product' strings read from the device,
- *	for later use in the SCSI simulator's INQUIRY data.
- *
- *	Set these strings here, in the case of 'product', using
- *	data read from the ATA IDENTIFY DEVICE page.
- *
- *	LOCKING:
- *	caller.
- */
-
-static void ata_dev_parse_strings(struct ata_device *dev)
-{
-	assert (dev->class == ATA_DEV_ATA);
-	memcpy(dev->vendor, "ATA     ", 8);
-
-	ata_dev_id_string(dev, dev->product, ATA_ID_PROD_OFS,
-			  sizeof(dev->product));
-}
-
 /**
  *	__ata_dev_select - Select device 0/1 on ATA bus
  *	@ap: ATA channel to manipulate
@@ -1127,8 +1104,6 @@ static void ata_dev_identify(struct ata_port *ap, unsigned int device)
 
 	ata_dump_id(dev);
 
-	ata_dev_parse_strings(dev);
-
 	/* ATA-specific feature tests */
 	if (dev->class == ATA_DEV_ATA) {
 		if (!ata_id_is_ata(dev))	/* sanity check */
@@ -3525,3 +3500,4 @@ EXPORT_SYMBOL_GPL(ata_scsi_error);
 EXPORT_SYMBOL_GPL(ata_scsi_slave_config);
 EXPORT_SYMBOL_GPL(ata_scsi_release);
 EXPORT_SYMBOL_GPL(ata_host_intr);
+EXPORT_SYMBOL_GPL(ata_dev_id_string);

drivers/scsi/libata-scsi.c

@@ -498,7 +498,9 @@ void ata_scsi_rbuf_fill(struct ata_scsi_args *args,
 unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,
 			       unsigned int buflen)
 {
-	const u8 hdr[] = {
+	struct ata_device *dev = args->dev;
+
+	u8 hdr[] = {
 		TYPE_DISK,
 		0,
 		0x5,	/* claim SPC-3 version compatibility */
@@ -506,14 +508,20 @@ unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,
 		96 - 4
 	};
 
+	/* set scsi removeable (RMB) bit per ata bit */
+	if (ata_id_removeable(dev))
+		hdr[1] |= (1 << 7);
+
 	VPRINTK("ENTER\n");
 
 	memcpy(rbuf, hdr, sizeof(hdr));
 
 	if (buflen > 36) {
-		memcpy(&rbuf[8], args->dev->vendor, 8);
-		memcpy(&rbuf[16], args->dev->product, 16);
-		memcpy(&rbuf[32], DRV_VERSION, 4);
+		memcpy(&rbuf[8], "ATA     ", 8);
+		ata_dev_id_string(dev, &rbuf[16], ATA_ID_PROD_OFS, 16);
+		ata_dev_id_string(dev, &rbuf[32], ATA_ID_FW_REV_OFS, 4);
+		if (rbuf[32] == 0 || rbuf[32] == ' ')
+			memcpy(&rbuf[32], "n/a ", 4);
 	}
 
 	if (buflen > 63) {

drivers/scsi/libata.h

@@ -36,8 +36,6 @@ struct ata_scsi_args {
 };
 
 /* libata-core.c */
-extern void ata_dev_id_string(struct ata_device *dev, unsigned char *s,
-			      unsigned int ofs, unsigned int len);
 extern struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,
 				      struct ata_device *dev);
 extern int ata_qc_issue(struct ata_queued_cmd *qc);

drivers/scsi/sata_sil.c

@@ -276,8 +276,14 @@ static void sil_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val)
 static void sil_dev_config(struct ata_port *ap, struct ata_device *dev)
 {
 	unsigned int n, quirks = 0;
-	const char *s = &dev->product[0];
-	unsigned int len = strnlen(s, sizeof(dev->product));
+	unsigned char model_num[40];
+	const char *s;
+	unsigned int len;
+
+	ata_dev_id_string(dev, model_num, ATA_ID_PROD_OFS,
+			  sizeof(model_num));
+	s = &model_num[0];
+	len = strnlen(s, sizeof(model_num));
 
 	/* ATAPI specifies that empty space is blank-filled; remove blanks */
 	while ((len > 0) && (s[len - 1] == ' '))

include/linux/ata.h

@@ -38,6 +38,7 @@ enum {
 
 	ATA_ID_WORDS		= 256,
 	ATA_ID_PROD_OFS		= 27,
+	ATA_ID_FW_REV_OFS	= 23,
 	ATA_ID_SERNO_OFS	= 10,
 	ATA_ID_MAJOR_VER	= 80,
 	ATA_ID_PIO_MODES	= 64,
@@ -205,6 +206,7 @@ struct ata_taskfile {
 #define ata_id_has_wcache(dev)	((dev)->id[82] & (1 << 5))
 #define ata_id_has_lba(dev)	((dev)->id[49] & (1 << 8))
 #define ata_id_has_dma(dev)	((dev)->id[49] & (1 << 9))
+#define ata_id_removeable(dev)	((dev)->id[0] & (1 << 7))
 #define ata_id_u32(dev,n)	\
 	(((u32) (dev)->id[(n) + 1] << 16) | ((u32) (dev)->id[(n)]))
 #define ata_id_u64(dev,n)	\

include/linux/libata.h

@@ -260,12 +260,6 @@ struct ata_device {
 	unsigned int		pio_mode;
 	unsigned int		udma_mode;
 
-	unsigned char		vendor[8];	/* space-padded, not ASCIIZ */
-	unsigned char		product[32];	/* WARNING: shorter than
-						 * ATAPI7 spec size, 40 ASCII
-						 * characters
-						 */
-
 	/* cache info about current transfer mode */
 	u8			xfer_protocol;	/* taskfile xfer protocol */
 	u8			read_cmd;	/* opcode to use on read */
@@ -398,6 +392,8 @@ extern int ata_port_start (struct ata_port *ap);
 extern void ata_port_stop (struct ata_port *ap);
 extern irqreturn_t ata_interrupt (int irq, void *dev_instance, struct pt_regs *regs);
 extern void ata_fill_sg(struct ata_queued_cmd *qc);
+extern void ata_dev_id_string(struct ata_device *dev, unsigned char *s,
+			      unsigned int ofs, unsigned int len);
 extern void ata_bmdma_setup_mmio (struct ata_queued_cmd *qc);
 extern void ata_bmdma_start_mmio (struct ata_queued_cmd *qc);
 extern void ata_bmdma_setup_pio (struct ata_queued_cmd *qc);